microRNAs in the pathogenesis of non-obstructive azoospermia: the underlying mechanisms and therapeutic potentials.

miRNAs are involved in different biological processes, including proliferation, differentiation, and apoptosis. Interestingly, 38% of the X chromosome-linked miRNAs are testis-specific and have crucial roles in regulating the renewal and cell cycle of spermatogonial stem cells. Previous studies demonstrated that abnormal expression of spermatogenesis-related miRNAs could lead to nonobstructive azoospermia (NOA). Moreover, differential miRNAs expression in seminal plasma of NOA patients has been reported compared to normozoospermic men. However, the role of miRNAs in NOA pathogenesis and the underlying mechanisms have not been comprehensively studied. Therefore, the aim of this review is to mechanistically describe the role of miRNAs in the pathogenesis of NOA and discuss the possibility of using the miRNAs as therapeutic targets.Abbreviations: AMO: anti-miRNA antisense oligonucleotide; AZF: azoospermia factor region; CDK: cyclin-dependent kinase; DAZ: deleted in azoospermia; ESCs: embryonic stem cells; FSH: follicle-stimulating hormone; ICSI: intracytoplasmic sperm injection; JAK/STAT: Janus kinase/signal transducers and activators of transcription; miRNA: micro-RNA; MLH1: Human mutL homolog l; NF-κB: Nuclear factor-kappa B; NOA: nonobstructive azoospermia; OA: obstructive azoospermia; PGCs: primordial germ cells; PI3K/AKT: Phosphatidylinositol 3-kinase/protein kinase B; Rb: retinoblastoma tumor suppressor; ROS: Reactive Oxygen Species; SCOS: Sertoli cell-only syndrome; SIRT: sirtuin; SNPs: single nucleotide polymorphisms; SSCs: spermatogonial stem cells; TESE: testicular sperm extraction; TGF-ß: transforming growth factor-beta.

Cytokines in embryonic secretome as potential markers for embryo selection.

Despite performing certain morphological assessments for selecting the best embryo for transfer, the results have not been satisfactory. Given the global tendency for performing quick and noninvasive tests for embryo selection, great efforts have been made to discover the predictive biomarkers of embryo implantation potential. In recent years, many factors have been detected in embryo culture media as a major source of embryo secretions. Previous studies have evaluated cytokines, miRNAs, extracellular vesicles, and other factors such as leukemia inhibitory factor, colony-stimulating factor, reactive oxygen species, soluble human leukocyte antigen G, amino acids, and apolipoproteins in these media. Given the key role of cytokines in embryo implantation, these factors can be considered promising molecules for predicting the implantation success of assisted reproductive technology (ART). The present study was conducted to review embryo-secreted molecules as potential biomarkers for embryo selection in ART.

Tacrolimus Improves the Implantation Rate in Patients with Elevated Th1/2 Helper Cell Ratio and Repeated Implantation Failure (RIF).

Introduction An abnormal endometrial immune response is involved in the pathogenesis of repeated implantation failure (RIF), so we investigated the effectiveness of tacrolimus treatment on the endometrium of RIF patients. Materials and Methods Ten RIF patients with elevated T-helper 1/T-helper 2 (Th1/Th2) cell ratios were recruited into a clinical study. The expression of p53, leukemia inhibitory factor (LIF), interleukin (IL)-4, IL-10, IL-17, and interferon gamma (IFN-γ) in the endometrium of patients with and without tacrolimus treatment and the association of these factors with assisted reproductive technology (ART) outcomes were investigated. Results Tacrolimus significantly increased the expression of LIF, IL-10, and IL-17 and decreased the expression of IL-4, IFN-γ, and the IFN-γ/IL-10 ratio in RIF patients. Tacrolimus treatment resulted in an implantation rate of 40%, a clinical pregnancy rate of 50%, and a live birth rate of 35% in RIF patients with elevated Th1/Th2 ratios who had previously failed to become pregnant despite at least three transfers of embryos. We also found a significant positive correlation between IL-10 levels and the implantation rate. Conclusions Our findings suggest that RIF patients with a higher Th1/Th2 ratio could be candidates for tacrolimus therapy and that this immunosuppressive drug could be acting through upregulation of LIF, IL-10, and IL-17.

N1-Methylnicotinamide: An Anti-Ovarian Aging Hormetin?

Ovarian aging occurs due to the reduction of the quality and quantity of the oocytes, and is regulated by mitochondrial survival and apoptotic signals. Reactive Oxygen Species (ROS) are one of those signals considered detrimental to cellular homeostasis. Nowadays, ROS are regarded as a regulatory factor at low levels as it induces the stress resistance which in turn increases the longevity. It is believed that the main mechanism for the life-promoting role of the ROS mediated by the 5' Adenosine Monophosphate-activated Protein Kinase (AMPK). N1-Methylnicotinamide (MNAM) is well known for its anti-diabetic, anti-thrombotic, and anti-inflammatory activity. Aldehyde oxidase 1 (AOX1) is a detoxifying enzyme, which metabolizes the MNAM and produces two metabolites including N1-methyl-2-pyridone-5- carboxamide (2py) and N1-methyl-4-pyridone-3-carboxamide (4py). The activity of AOX1 enhances the production of ROS and improves the longevity. It has been reported that the MNAM could postpone the aging through the induction of low-level stress. It has been documented that the production of MNAM is significantly higher in the cumulus cells of the patients with Polycystic Ovary Syndrome (PCOS) and its administration on the rat model of PCOS has been shown to alleviate the hyperandrogenism and successfully activate the ovarian AMPK. Therefore, it can be hypothesized that the anti-ovarian aging effects of the MNAM are possibly based on the activation of AMPK through transient elevation of the ROS.

Nicotinamide and its metabolite N1-Methylnicotinamide alleviate endocrine and metabolic abnormalities in adipose and ovarian tissues in rat model of Polycystic Ovary Syndrome.

Polycystic Ovary Syndrome (PCOS), as a common endocrine disorder is accompanied by hyperandrogenism, insulin resistance, ovulation problems, and infertility. Various types of off-label drugs like metformin have been used for the management of targeted problems caused by PCOS such as insulin resistance and hyperandrogenism. Nicotinamide (NAM) acts as a substrate of visfatin and Nicotinamide N-Methyltransferase (NNMT) leading to the generation of Nicotinamide Adenine Dinucleotide (NAD) and N1-Methylnicotinamide (MNAM), respectively. MNAM is known as an anti-inflammatory, anti-thrombosis, and anti-diabetic agent. In this study, the effects of NAM and MNAM on metabolic and endocrine abnormalities were evaluated in the adipose and ovarian tissues of a letrozole-induced rat model of PCOS. Our results showed that MNAM and NAM reversed abnormal estrous cycle and reduced the serum testosterone levels and CYP17A1 gene expression. Furthermore, all therapeutic factors improved HOMA-IR after treatment and NAM significantly increased the expression of GLUT4 and decreased the gene expression of visfatin. Also, MNAM diminished the gene expression of visfatin and resistin. It is noteworthy that all the therapeutic factors successfully activated the AMPK. In summary, this study is the first study reported beneficial effects of NAM and MNAM on the treatment of PCOS. Additionally, the alleviative effects of our therapeutic factors may be partially mediated by the AMPK-dependent manner due to the contribution of the AMPK in the expression of CYP17A1, visfatin, resistin, and GLUT4. Although more studies are required to unravel the exact mode of actions of MNAM and NAM in the PCOS, the findings of the current study shed light on an urgent need for discovering novel therapeutic pharmaceuticals regarding the treatment of PCOS.

S100 protein family and embryo implantation.

It is well known that embryo implantation is a critical process in which embryo should be able to reach and attach to endometrium. Until now, various types of factors are involved in the regulation of this process. S100 proteins are calcium-binding proteins, which have vital roles in embryo implantation and have been considered as possible candidate markers for endometrial receptivity. However, studies regarding mode of actions of these proteins are scarce and more mechanistic insights are needed to clarify exact roles of each one of the S100 protein family. Understanding of function of these proteins in different compartments, stages, and phases of endometrium, could pave the way for conducting studies regarding the therapeutic significance of these proteins in some disorders such as recurrent implantation failure. In this review, we outlined roles and possible underlying mechanisms of S100 protein family in embryo implantation.

Lymphocytes immunotherapy for preserving pregnancy: Mechanisms and Challenges.

Due to the expression of paternal antigens by the embryo, pregnancy is considered as a semi-allograft and so immunological dysregulation is considered as one of the important causes in repeated implantation failure (RIF) and recurrent pregnancy loss (RPL). It has been revealed that lymphocytes immunotherapy (LIT) could be an appropriate approach to prevent pregnancy loss in such patients. Various mechanisms have been suggested for effectiveness of LIT such as enhancing expression of anti-paternal cytotoxic antibodies (APCA), progesterone-induced blocking factor (PIBF), anti-idiotypic antibodies (Ab2), and mixed lymphocyte reaction blocking antibodies (MLR-Bf), as well as reduction in the T helper 1/T helper 2 ratio and deviation in the pattern of cytokines production. However, there are controversial results about the beneficial effect of LIT treatment in RIF and RPL patients. In the current study, we reviewed findings of LIT in RIF and RPL patients with a focus on possible mechanisms of alloimmunization in preserving pregnancy. Besides, we highlighted possible reasons for mixed results about the effectiveness of LIT and way of solving the problem. Also, we proposed potential laboratory and clinical criteria to recruit patients for LIT.